Konjac, with the botanical name Amorphophallus konjac, is a perennial plant of the Araceae family that grows from a spherical bulb that can easily reach 3 to 4 kilos, and sometimes up to 20 kilos after several years of cultivation. This amazing plant grows naturally in Asia (China, Japan, Indonesia, Korea…) where its bulb has been consumed in different ways for a very long time, both for its virtues and for its nutritional value.

Today, food and cosmetic products made from Konjac are gaining an increasingly important place on store shelves in the West, and particularly in Europe. Konjac flour noodles or konjac sponges are probably the flag bearers (more info on the uses of the plant). Konjac is also a very decorative plant with its unusual and immense flowering which can reach nearly 50 cm in height! It is a plant that is both curious, easy to grow and interesting from a culinary point of view, hence my desire to give you a little apology for this little-known plant and its culture! Why not grow French Konjac in your vegetable garden?

How to grow and produce Konjac properly in France ?

Despite the strong agricultural and economic potential of Konjac, its cultivation in Europe and France is currently only on the confidential scale of garden collectors. The tuber of Amorphophallus konjac is increasingly sought after for its nutritional and dietetic qualities, to the point that demand has outstripped supply in recent years! Today, almost all of the world’s Konjac flour production (about 30,000 tons per year) is made in China and Japan.

To guarantee a quality Konjac, durable and without treatment, it is therefore particularly interesting to cultivate it directly in your vegetable garden. We have been experimenting with its cultivation here in Alsace for several years now, and it even turns out that its resistance to cold is quite high, much higher than the minimum indicated in the literature. Indeed, under a layer of about twenty centimeters of mulching during the winter period, its bulb remains in place without problem in the ground from one year to another despite occasional negative temperatures, of the order of -12 /-15°C.

Konjac foliage, bottom view – Photo: Alsagarden.

The bulbs can also be removed from the ground for the winter and stored in a dry place until spring, it is generally recommended, especially in poorly drained soils, or with excessive water retention capacity which can lead to rotting of the bulbs. tubers during the period of vegetative rest. This is also how the plant is grown in Asia. The longer the bulb is grown, the greater its weight becomes. Generally, the final harvest is carried out between 3 and 4 years. The first year, the young tubers of about ten grams are planted in the spring and then harvested in the fall, around mid-November before the cold. They are then planted again and harvested the following two years before the final harvest, generally in the third year, to obtain tubers weighing between 1 and 4 kilos.

For its cultivation, Konjac appreciates soils rich in organic matter, drained and fresh. As far as light is concerned, this plant prefers semi-shaded exposures. Avoid a location in full sun, especially during the hottest hours of the day, which would cause burning and drying of the foliage.

Konjac in the ground in Alsace – Photo: Alsagarden

Become a pioneer of Konjac cultivation in Europe !

We have been growing a strain of Konjac for almost ten years in the ground, now perfectly acclimatized to our climate. We have applied ourselves during all these years to develop, multiply and select the most resistant Konjac plants with the best yield, while improving our cultivation techniques, in the ground and in pots. With our experience in the cultivation and harvesting of this tuber, we are now ready to offer bulbs and young plants for sale to amateur gardeners and market gardeners wishing to develop their culture in France and wishing to offer an alternative to the Konjac produced and imported from ‘Asia.

Do you want to become a pioneer in France of Konjac culture? Go to our online store to order, depending on the season, young plants or bulbs! You are a market gardener and you would be interested in growing Konjac on a larger scale, please contact us for more information, or for any technical or price request.

Lucas Heitz, The Curious Gardener

Landscape gardener and geographer, I am passionate about the plant world and its countless curiosities. Founder of the Alsagarden blog and activist for gardening in harmony with Nature, I am also a French gardener, fervent defender of Heritage varieties.